* {
  padding: 0;
  margin: 0;
}

body {
  height: 100vh;
  background: #e7e7e7 url(../img/beij.png) center no-repeat fixed;
  background-size: cover;
  backdrop-filter: blur(5px);
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  background-color: #e7e7e7;
  border-radius: 0.7rem;
  box-shadow:
    0 0.9rem 1.7rem rgba(0, 0, 0, 0.25), 0 0.7rem 0.7rem rgba(0, 0, 0, 0.22);
  height: 420px;
  max-width: 750px;
  overflow: hidden;
  position: relative;
  width: 100%;
}

.container-form {
  height: 100%;
  position: absolute;
  top: 0;
  transition: all 0.6s ease-in-out;
}

.container-signin {
  left: 0;
  width: 50%;
  z-index: 2;
}

.container-signup {
  left: 0;
  opacity: 0;
  width: 50%;
  z-index: 1;
}

.form {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  padding: 0 3rem;
  height: 100%;
  text-align: center;
  background-color: #e7e7e7;
}

.form-title {
  font-weight: 300;
  margin: 0;
  margin-bottom: 1.25rem;
}

.link {
  color: #333;
  font-size: 0.9rem;
  margin: 1.5rem 0;
  text-decoration: none;
}

.input {
  width: 100%;
  background-color: #fff;
  padding: 0.5rem 0;
  margin: none;
  outline: none;
}

.btn {
  background-color: #df3033;
  box-shadow: 0 4px rgba(255, 112, 159, .3);
  color: #e7e7e7;
  border: none;
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: bold;
  letter-spacing: 0.1rem;
  padding: 0.9rem 4rem;
  text-transform: uppercase;
  transition: transform 80ms ease-in;
}

.form>.btn {
  margin-top: 1.5rem;
}

.btn:active {
  transform: scale(0.95);
}

.container-overlay {
  height: 100%;
  left: 50%;
  overflow: hidden;
  position: absolute;
  top: 0;
  transition: transfrom 0.6s ease-in-out;
  width: 50%;
  z-index: 100;
}

.overlay {
  width: 200%;
  height: 100%;
  position: relative;
  left: -100%;
  background: url(bg.jpg) no-repeat center fixed;
  background-size: cover;
  transition: transform 0.6s ease-in-out;
  transform: translateX(0);
}

.overlay-panel {
  height: 100%;
  width: 50%;
  position: absolute;
  top: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  transform: translateX(0);
  transition: transform 0.6s ease-in-out;
}

.overlay-left {
  transform: translateX(-20%);
}

.overlay-right {
  right: 0;
  transform: translateX(0);
}

.panel-active .overlay-left {
  transform: translateX(0);
}

.panel-active .container-overlay {
  transform: translateX(-100%);
}

.panel-active .overlay {
  transform: translateX(50%);
}

.panel-active .container-signin {
  transform: translateX(100%);
}

.panel-active .container-signup {
  opacity: 1;
  z-index: 5;
  transform: translateX(100%);
}

.btn a {
  color: #fff;
}